Clothes Dryer

ABSTRACT

A clothes dryer is provided. In the dryer, air flowing into a drying container is provided with heat from heat pump. The clothes dryer comprises a cabinet, a drying container rotationally mounted in the cabinet, a motor providing the container with rotational force, a first air path connected to a side of the container, a second air path connected to another side of the container and to the outside of the cabinet, and a first heat exchanging member and a second heat exchanging member in the first air path. A damper may be additionally included in the second air path.

TECHNICAL FIELD

The present invention relates to a clothes dryer, and more particularly,to a clothes dryer of exhaust type including a vapor compression cyclesystem. The clothes dryer improves drying efficiency by drying laundryby supplying heat to an introduced air from a heat exchange cyclesystem.

BACKGROUND ART

Clothes dryers are mainly used to dry clothes by removing moisture fromclothes that have just been washed.

The clothes dryers can be classified into an exhaust type and acondensation type according to a processing method of moist airgenerated while drying laundry. The former type employs a method ofexhausting moist air from a dryer, while the latter employs a method ofremoving moisture by condensing moist air exhausted from a dryer andcirculating the moisture-removed air again in the dryer.

Typically, in the exhaust type dryer, an air intake duct and an airexhaust duct are connected to a rotatable drum disposed inside acabinet, the air intake duct having a heater disposed therein.

As air outside the dryer is introduced into the air intake duct bydriving a fan, the air is heated to a high temperature by a heater. Theheating temperature reaches up to about 100° C. This high temperatureair is introduced into a drying drum in the dryer, thus drying laundryin the drum. In the drying procedure, the high temperature air gets tocontain the moisture included in the laundry, and high humidity air isdischarged through the air exhaust duct. Although such a conventionalclothes dryer that delivers heat to an introduced air by using a heaterhas a merit that the overall drying time is shortened by the heater'srapid heating of air and it can be manufactured to have a largecapacity, it has a drawback that the energy consumption is large becausean introduced air is heated by the heater. Especially, there is a greatprobability that damages may occur depending on the material of laundryin the drying procedure since the laundry is dried with air of hightemperature of 100° C. or higher.

Meanwhile, the condensation type clothes dryer has a merit that it canbe manufactured in a built-in type since it requires no air exhaust ductfor discharging air out of the clothes dryer, while it has a drawbackthat it requires a long drying time and is difficult to be manufacturedto have a large capacity although its energy efficiency is higher thanthe exhaust type. Under this background, there is a demand for a clothesdryer that provides a high energy efficiency and is so improved that itmay not cause a damage to laundry.

Meanwhile, in areas with a high humidity, for example, near seashores orareas with a long rain season, there is a problem in that the dryingefficiency is relatively lower when the clothes dryer is used. This isbecause a large amount of moisture is contained in the air used to drylaundry. It requires a lot of time to dry laundry since the aircontaining a large amount of moisture is introduced into the drying drumwith the moisture not being removed enough even if the air is increasedin temperature by the heater, resultantly increasing the energyconsumption required to complete the drying. Subsequently, there is ademand for a clothes dryer for supplying air to a drying drum withmoisture removed enough from an introduced air.

DISCLOSURE OF THE INVENTION

Therefore, an object of the present invention is to provide a clothesdryer which improves energy efficiency and has little possibility ofcausing a damage to laundry due to a high temperature air in a dryingprocedure.

Another object of the present invention is to provide a clothes dryerwhich can introduce air to a drying drum with moisture removed enoughfrom the introduced air.

Still another object of the present invention is to provide a clothesdryer which is compact with improved space utilization.

To achieve the above objects, according to a first aspect of the presentinvention, there is provided a clothes dryer, comprising: a cabinet; adrying container rotationally mounted in the cabinet; a driving portionfor supplying a torque to the drying container; a first air pathconnected to one side of the drying container; a second air pathconnected to the other side of the drying container and connected tooutside of the cabinet; and first and second heat exchange portions forexchanging heat with air introduced into the first air path.

Preferably, the first air path and the second air path are located belowthe drying container, and the first heat exchange portion is located infront of the second heat exchange portion on the first air path.

The cabinet is provided at the front face with an opening for puttinglaundry in and out of the drying container.

A fan for creating an air flow is disposed at least one of the first andsecond air paths. Preferably, the fan receives a torque from the drivingportion.

According to a second aspect of the present invention, there is providedcomprising: a cabinet; a drying container rotationally mounted in thecabinet; a driving portion for supplying a torque to the dryingcontainer; a first air path connected to one side of the dryingcontainer; a second air path connected to the other side of the dryingcontainer and connected to outside of the cabinet; and first and secondheat exchange portions for exchanging heat with air introduced into thefirst air path, wherein the second air path has a damper for opening andclosing the paths disposed thereon.

A temperature sensor or humidity sensor is disposed in front of thedamper on the second air path. The damper is controlled in at least twostates including an opened state and a closed state according to apredetermined value of a signal sensed by the temperature sensor orhumidity sensor.

According to a second aspect of the present invention, there is providedcomprising: a cabinet; a drying container rotationally mounted in thecabinet; a driving portion for supplying a torque to the dryingcontainer; a first air path connected to one side of the dryingcontainer; a second air path connected to the other side of the dryingcontainer and connected to outside of the cabinet; and first and secondheat exchange portions for exchanging heat with air introduced into thefirst air path, wherein an auxiliary air inlet is formed on the firstair path.

Preferably, the auxiliary air inlet is formed between the first heatexchange portion and the second heat exchange portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is a perspective view showing the outer appearance of a clothesdryer;

FIG. 2 is a perspective view showing the inside of a clothes dryeraccording to one embodiment of the present invention;

FIG. 3 is a perspective view showing the inside of a clothes dryeraccording to one embodiment of the present invention;

FIG. 4 is a plan view showing parts disposed on the bottom of theclothes dryer of FIG. 2;

FIG. 5 is a schematic view showing a refrigerant flow and an air flow inthe clothes dryer according to the present invention;

FIG. 6 is a perspective view showing some parts of the inside of theclothes dryer according to the present invention;

FIG. 7 is a plan view showing an air flow introduced into the clothesdryer;

FIG. 8 is a schematic view showing some parts of the clothes dryerprovided with a damper; and

FIG. 9 is a graph showing a rate of change in temperature (or humidity)in the drying container.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in more detail with reference to the accompanying drawings.

While the invention has been described in connection with preferredembodiments, it is not intended to limit the scope of the invention tothe particular form set forth, but on the contrary, it is intended tocover such alternatives, modifications, and equivalents as may beincluded within the spirit and scope of the invention as defined by theappended claims.

First, referring to FIG. 1, one example of a clothes dryer 10 accordingto the present invention is illustrated. A cabinet 12 provided with anentrance 14 in the front face is hollow inside, with a drying containerrotationally mounted therein.

FIGS. 2 and 3 illustrates an inner structure of the clothes dryer inmore detail.

The drying container 16 is a cylindrical-shaped structure, and disposedso as to rotate around an axis substantially parallel to the bottom ofthe cabinet 12.

The drying container 16 is made rotatable by receiving a torque from adriving portion 18, e.g., a motor, disposed on a lower side thereof,preferably, on the bottom of the cabinet 12. Typically, as a torquetransmission means, a belt engaged by being extended from a drivingshaft of the driving portion 18 to the outer peripheral surface of thedrying container 16 is suitable. As described later, the driving portionis also able to transmit a torque to a fan 40 disposed inside thecabinet 12 and creating an air flow.

FIG. 4 illustrates various elements disposed on the bottom of thecabinet of the clothes dryer. As illustrated in FIGS. 2 to 4, a firstair channel 20 through which intake air flows is connected to at oneside of the drying container 16, and a second air path 22 through whichexhaust air from the drying container flows is connected to the otherside thereof. It does not matter if the entrance of the first air path20 is not exposed out of the cabinet 12, but it is preferable that theoutlet of the second air path 22 is exposed out of the cabinet 12. theshapes of the first air path 20 and second air path 22 are notspecifically restricted, but the direction or position of each part ofthe paths may be changed so as to be suitable to the space in thecabinet.

A first heat exchange portion 30 and a second heat exchange portion 32are disposed in the first air path 20. The heat exchange portions 30 and32 remove moisture by removing heat from the air flowing into the firstair path 20, and increases the temperature of the air by applying heat.Thus, the air passing through the first air path 20 enters the dryingcontainer 16 in a dried and temperature-increased state.

It is preferable that the first heat exchange portion 30 and the secondheat exchange portion 32 form a thermodynamic cycle. For this, thecabinet 12 further includes a compressor 34 and an expansion device 36are preferably disposed in the lower side of the drying container orlower than the drying container. The first heat exchange portion 30 andthe second heat exchange portion 32 are connected by a pipe 38 to formone closed loop. Such a cycle is a kind of “vapor compression cycle”,and serves as a heat pump with respect to air flowing through the firstair channel 30.

FIG. 5 schematically illustrates a refrigerant flow and an air flow inthe aforementioned cycle. A proper refrigerant flows in the pipe 38 forconnecting each of the elements of the cycle. As for the directionthereof, the refrigerant proceeds to the first heat exchange portion 30from the second heat exchange portion 32 through the expansion device36, and then proceeds to the second heat exchange portion 32 from thefirst heat exchange portion 30 through the compressor 34. This flowdirection of the refrigerant is indicated by a dotted arrow.

The air flowing into the first air path 20 passes through the two heatexchange portions 30 and 32 and enters the drying container 16, and thenis exhausted via the second air path 22. This flow direction isindicated by a dotted arrow.

It is preferable that the air entering the first air path 20 enters thedrying container in a dried state after it is increased in temperatureby firstly having its moisture removed in the first heat exchangeportion 30 and then receiving heat from the second heat exchange portion32. Therefore, it is preferable that an evaporator for absorbing heatfrom a flowing air is used is used as the first heat exchange portion30, a condenser for supplying heat to a flowing air is used as thesecond heat exchange portion 32, and the first heat exchange portion isdisposed more forward than the second heat exchange portion is.

A plurality of heat exchange pins are generally mounted at the heatexchange portions 30 and 32 in order to increase a heat transfer area onthe pipe through which refrigerant passes. A flowing air firstlydelivers heat to the evaporator to remove its moisture while evaporatingthe refrigerant, and then receives heat from the condenser to beincreased to a temperature higher than about 50° C., preferably, 50 to75° C.

Preferably, each of the elements constituting the above cycle, that is,the first heat exchange portion 30, the second heat exchange portion 32,the compressor 34, the expansion device, and the pipe 38 connecting themare all disposed inside the cabinet 12, especially, below the dryingcontainer 16. For this, it is appropriate that at least some parts ofthe first air path, where the first heat exchange portion 30 and thesecond heat exchange portion 32 are disposed, are disposed below thedrying container 16, and at least some parts of the second air path 22are disposed below the drying container 16 too.

By this arrangement, there is no need to increase the volume of thecabinet, thus the inner space can be utilized efficiently, resultantlymaking the clothes dryer compact. If the aforementioned elements areexposed out of the clothes dryer or the volume of the cabinet isincreased, the installation area of the clothes dryer in a buildingbecomes larger, thereby decreasing the spatial utilization.

FIG. 6 illustrates some parts of the clothes dryer according to thepresent invention. As illustrated therein, a belt 42 is wound around theouter peripheral surface of the drying container 16, and the belt 42 isconnected to a rotary shaft 18 a of the driving portion 18 and transfersa torque to the drying container 16. The driving portion 18 is alsoconnected to a fan 40 disposed on the second air path 22 to drive thefan. Thus, the driving portion 18 can rotate the drying container 16 andthe fan 40 simultaneously. As above, the drying container 16 and the fan40 are driven at a time only by the one driving portion 18, so that thespace utilization in the cabinet can be increased and no additionalapparatus is required, which is advantageous. Although, in FIG. 6, thefan 40 is disposed in the second air path 22 near the drying container16, it may also be disposed on the first air path only if it can besupplied with a torque from the driving portion 18.

Meanwhile, a filter (21 of FIG. 3) is disposed on the first air path 20before the first heat exchange portion is disposed, so that it mayremove contaminants, such as dusts, contained in an introduced air inadvance.

A drying process of the clothes dryer of the present invention havingthis construction will be described below.

When the fan 40 is driven by the rotation of the driving portion 18, asuction force is generated to introduce external air to the entrance ofthe first air path 20. As the introduced air passes through the firstheat exchange portion 30, the moisture contained in the air is removedthrough a first heat exchange. The air changed to a low temperature andlow humidity while passing through the first heat exchange portion 32undergoes a secondary heat exchange while passing the second heatexchange portion 32 of a high temperature. The air changed to a hightemperature and low humidity continuously passes through the inside ofthe first air path 20 and reaches to one side of the drying container16.

The air having passed through the second heat exchange 32 maintains atemperature of about 50 to 75° C. The high temperature air maintainingthis degree of temperature can smoothly perform drying without damaginglaundry in the drying container 16.

The high temperature and low humidity introduced into the dryingcontainer 16 delivers heat while in contact with laundry containingmoisture, and receives moisture from laundry and comes out of the dryingcontainer in the form of a high humidity air. The high humidity airflown out of the drying container is exhausted out of the cabinet 12through the second air path 22.

In the clothes dryer according to the present invention, a heatgenerating system using a vapor compression cycle exhibits heatingperformance two or three times larger as compared to a heater type,under the assumption that the same power is used. Thus, powerconsumption can be reduced.

Further, the temperature of air introduced into the drying container islower as compared to drying using a heater type, which causes lessdamage of laundry.

Besides, the first heat exchange portion of the heat generating systemremoves moisture from the air introduced into the first air path, thusdries laundry with low humidity air. Therefore, the drying efficiency isimproved. Especially, the clothes dryer of this invention is effectiveto dry clothes in humid areas.

If the clothes dryer is used in dry areas, no moisture removal processaccompanied by a heat exchange in the first heat exchange portion wouldbe required. Further, since the temperature of air becomes lower in themoisture removal process, the efficiency of the overall system may bedegraded. Thus, there is a need to make the second heat exchange portionand the air directly contact with each other without undergoing the heatexchange in the first heat exchange portion.

FIG. 7 illustrates a clothes dryer of a modified structure according toanother embodiment of the present invention. Air is introduced into afilter 21 disposed at the entrance side of the first air path 20.Further, an auxiliary air inlet 50 is formed at a side of the first airpath. The auxiliary air inlet 50 may be exposed out of the cabinet 12 asshown in the drawing, or may not be exposed. The auxiliary air inlet 50is preferably formed at a side of the first air path between the firstheat exchange portion 30 and the second heat exchange portion 32. Afilter 51 for removing dusts contained in external air may be disposedon the auxiliary air inlet 50.

By forming the auxiliary air inlet 50, the first air path 20 has two airinlets. The air supplied to the drying container 16 via the first airpath contains the air passing through the first heat exchange portion 30and the air directly passing though the heat exchange portion 32 withoutpassing through the first heat exchange portion. The air introduced viathe auxiliary air inlet 50 and only passing through the second heatexchange portion 32 has no heat loss caused by heat exchange with thefirst heat exchange portion 30, thus it can be introduced into thedrying container 16 in a relatively high temperature state.

As above, by varying the air inlets of the first air path, the airsupplied to the drying container can obtain a dual effect of heat lossreduction and moisture removal. Further, the overall efficiency of thevapor compression cycle system can be improved.

Hereinafter, a clothes dryer according to a second aspect of the presentinvention will be described.

An exhaust type dryer injects high temperature air to one side of adrying container, and discharges humid air to the other side thereof.Such a process is always the same from an initial stage of drying untilan end stage of drying. If high temperature air stays in the dryingcontainer for a while and then is directly discharged out of the dryingdrum, this is not efficient in terms of energy utilization. That is,energy consumption is increased in the overall drying process.

In the present invention, the energy efficiency is increased bycontrolling an air flow such that the time during which air stays in thedrying container may differ depending on a drying procedure. In apreferred embodiment, a damper for opening and closing the paths isdisposed on the second air path through which air is discharged to thuscontrol an air flow.

FIG. 8 schematically illustrates some parts of the clothes dryer with adamper disposed thereto.

A damper 60 is disposed near the drying container 16 on the second airpath 22.

A sensor 63 for sensing a temperature or humidity of air discharged fromthe drying container 16 is disposed in front of the damper 60. Thedamper 60 is controlled according to a temperature or humidity sensed bythe sensor 62, thereby adjusting the flow of air passing through thesecond air path 22.

A method of controlling the opening and closing of the damper can beselected variously according to a dried state of laundry or a state ofthe air discharged from the drying container.

Referring to FIG. 9, a rate of change per time in temperature (A) orhumidity (B) of air discharged from the drying container is shown. Adegree of opening and closing the damper may be changed based on asaturation point Ps at which an increase rate of temperature sensed bythe sensor becomes lower or a decrease rate of humidity becomes slow.

For example, it is possible to control the damper to be closed if ameasured temperature of an air outlet portion of the drying container isless than a predetermined temperature (i.e., 60° C.) or control thedamper to be opened if it is greater than the predetermined temperature.Besides, it is also possible to close the damper until a measuredhumidity of air discharged from the air outlet portion of the dryingcontainer reaches a predetermined value and open the damper if itexceeds the predetermined value.

By this method, the damper is closed in an initial stage of drying toincrease the time during which a high temperature air stays in thedrying container, and the damper is opened in an intermediate or endstage of drying to increase a discharge amount of air. Therefore, thereis a lot of time for which high temperature air is contacted withlaundry in the initial stage of drying, thus even a small air flow canbe efficiently utilized for drying. Further, in the intermediate or endstage of drying, the energy consumption can be reduced by decreasing anair heating degree rather than by increasing an air flow amount.

Meanwhile, if the damper is fully opened for a long time, the pressurein the drying container may be excessively increased or a large load maybe applied to the fan for creating an air flow. To prevent this, thestep of partially opening the damper may be included.

That is, a multistage damper control method may be used in which thedamper is fully opened if a measured pressure in the drying containerreaches a predetermined pressure or if a temperature or humidity reachesa predetermined value after the damper is slightly opened in advancewhen the temperature or humidity reaches a given value before the airoutlet in the drying container reaches the predetermined temperature orhumidity.

As described above, the present invention can properly control ahumidity and temperature of air introduced to the drying container byincluding first and second heat exchange portions serving as heat pumps.

Furthermore, if the vapor compression cycle system is disposed below thedrying container as in the present invention, the internal structure ofthe dryer is utilized as its, and thus there is no need for volumeincrease. That is, the space required to dispose the system gets smalleras compared to the case where the system is disposed at a side or rearof the cabinet.

Besides, the present invention can control an air path resistance bychanging the degree of opening and closing the damper disposed betweenthe drying container and the air path. When the air path resistance isincreased, the time for which high temperature air stays in the dryingdrum can be lengthened, thereby removing a lot of moisture from laundry.Consequently, the energy consumption of the dryer can be reduced.

1. Clothes dryer, comprising: a cabinet; a drying container rotationallymounted in the cabinet; a motor providing the container with rotationalforce; a first air path connected to a side of the container; a secondair path connected to another side of the container and to the outsideof the cabinet; and a first heat exchanging member and a second heatexchanging member in the first air path.
 2. The clothes dryer of claim1, wherein the first air path and the second air path are on the lowerpart of the cabinet.
 3. The clothes dryer of claim 1, wherein the firstheat exchanging member removes the moisture of air flowing in the secondair path and the second heat exchanging member increases the temperatureof air flowing in the first air path.
 4. The clothes dryer of claim 3,wherein the first heat exchanging member is ahead of the second heatexchanging member.
 5. The clothes dryer of claim 3, further comprising acompressor, an expanding member, and connecting pipes, wherein the firstheat exchanging member and the second heat exchanging member communicatewith each other in thermodynamic cycle.
 6. The clothes dryer of claim 5,wherein the first heat exchanging member is an evaporator which suppliesheat from air flowing in the second path to refrigerant and the secondheat exchanging member is a condenser which supplies heat fromrefrigerant to air flowing in the first air path.
 7. The clothes dryerof claim 5, wherein the compressor and the expanding member are on thelower part of the cabinet.
 8. The clothes dryer of claim 1, wherein anopening part is formed at the front side of the cabinet.
 9. The clothesdryer of claim 1, wherein a fan for causing air flow is placed at leastone of the first air path and the second air path, said fan receivingrotational force from the motor.
 10. The clothes dryer of claim 9,wherein the fan is placed at the second air path.
 11. The clothes dryerof claim 1, wherein air of 50˜75° C. flows into the drying container viathe first air path.
 12. The clothes dryer of claim 1, wherein a filteris placed ahead of the first heat exchanging member and in the first airpath.
 13. The clothes dryer of claim 1, wherein a damper for opening andclosing air path is placed in the second air path.
 14. The clothes dryerof claim 15, wherein a temperature sensor or a humidity sensor is aheadof the damper in the second air path.
 15. The clothes dryer of claim 14,wherein the damper is controlled in at least two states including openstate and close state, depending on signal from the temperature sensoror the humidity sensor.
 16. The clothes dryer of claim 1, wherein anauxiliary air inlet is formed in the first air path.
 17. The clothesdryer of claim 1, wherein the auxiliary air inlet is placed between thefirst heat exchanging member and the second heat exchanging member. 18.The clothes dryer of claim 1, wherein a filter is placed in theauxiliary air inlet.